Internal-combustion engine



Nov. 15, 1927.

M. PLASS INTERNAL COMBUSTION ENGINE Filed Sept. 27, 1924 5 Sheets-Sheet1 INVENTOR: A/mf'rm Pia/15$,

ATTORNEY. I

Nov. 15, 1927. 1,649,544

M. PLASS INTERNAL COMBUSTION ENGINE 1 Filed Sept. 27, 1924 5Sheets-Sheet 2 82% IAW/ INVENTOR.

A/Aer/M Bmss,

ATTORNEY.

Nov. 15, 1927. 1,649,544

M. PLASS INTERNAL COMBUSTION ENGINE Filed Sept. 27, 1924 5 Sheets-Sheet3 E Q as Q I:

INVENTOR.

MmPr/N finss,

TTORNEY.

New. 15, 1927; I M. PLASS INTERNAL COMBUSTION ENGINE 5 Sheets-Sheet 4Filed Sept. 27, 1924 I INVENTOR:

M/i/ITl/Y 2 1/955.

5 ATTORNEY.

M. PLA'ss INTERNAL COMBUSTION ENGINE 5 Sheets-Sheet 5 FIG. X

Filed Sept. 27, 1924 INVENTOR.

Men/v B1 4 A TTORNEY.

Patented Nov. 15, 1927.

PATENT OFFICE.

MARTIN PLASS, OF HATFIELD, PENNSYLVANIA.

INTERNAL-COBIBUSTION ENGINE.

Application filed September 27, 1924.

DIy improvement relates to engines of the two cycle type, andparticularly to means for controlling the. admission of the comln1stiblemixture and the expulsion of the products oi combustion.

As hereinafter described; my invention includes the combination with anouter cylinder easing, having water jacket recc cast in its inner walls,said recesses being primarily open inwardly of stationary eylin dricalsleeves forming the inner walls oi. said jacket recesses; rotary tubularvalves mounted to turn in said sleeves to vary the eii'ec tive area ofports in the latter; said sleeves and valves being of larger diametersat their ends near the crank shaft: and pistons mounted to reciprocatein said valves; the larger diameters of the pistons cooperating with thelarger diameters of the valves to form charging pump chambers betweenthem to alternately intake and charge the conihustible mixture into thecombustion. power, chambers, which are in the smaller diamctricalportions of said valves.

My invention also includes the various novel features of constructionand arrangement hereinafter more definitely specified.

In said drawings; Fig. I is a longitudinal sectional view through theaxes ot the cylinders of a two cylinder two cycle engine embodying myinvention.

Fig. II is a transverse sectional view, taken on the line II, II in Fig.I, and through the axis of one of said cylinders and at right angles toFig. I.

Fig. III is a transverse sectional view taken on the line III, III inFig. I. at right angles to the axis of said cylinders.

Fig. IV is a transverse sectional view, taken on the line IV, IV in Fig.I, at rightangles to the axis of said cylinders.

Fig. V is a transverse sectional view. taken on the line V, V in Fig. I,at right angles to the axis of said cylinders.

VI is a diagram indicating steps in the operation of the power cylinderof said engine.

Fig. VII is a diagram indicating steps in the operation of the chargingcylinder of said engine.

Fig. VIII is a longitudinal side elevation of a four cylinder. twocycle, engine embodying my invention.

Serial No. 740,208.

Fig. IX is a transverse sectional View, taken on the line IX, IX in Fig.VIII at right angles to the axis ot the engine cylinders.

Fig. X is a fragmentary transverse sectional view, taken on the line X,parallel with the axes of the cylinders in Fig. VIII.

Fig. XI is a diagram indicating the steps in the operation of the engineshown in Figs. VIII to X inclusive.

Referring to the form of my invention shown in Figs. 1 to 7 inclusive;the cylinder caziiug 1, conveniently formed as a single casting havingwater jacket recesses 2, pri marily open at their inner sides andrespectively surrounding the cylindrical bores ot which there are two insaid casing. ba'id using 1 is enlarged at the inner ends of said jacket.recesses 2, to form the admission chamber 5, having the intake port (3,as shown in Figs. II and III. As shown in Fig. III; said admissionchamber also has a series of valve ports 7, opening inwardly through theannular reinforcing web 8, intermediate ot the length of said chamber.Said casing 1 is also enlarged, near its outer end, to form the exhaustchamber 9 which, as shown in Figs. II and IV, has the outlet port 10.Said exhaust chamber 9 also has, between said water jacket recesses 2,circular series of exhaust valve ports 11, opening inwardly around therespective cylindrical bores 3.

As best shown in Figs. I and II; said cylindrical bores 33 are ofsmaller diameter at their outer ends than at their inner ends. and theports 7 are presented in a conical Zone intermediate ot the larger andsmaller diameters of said bores. As shown in Figs. I and II; each ofsaid bores 3 is lined with a, primarily separate, stationary sleeve 13having cylindrical portions of different diameters connected by aconical zone, fitted to said bores; said sleeves being fitted to saidcasing 1 in water tight relation therewith, so as to form the innerwalls of the water jacket recesses 2 aforesaid. Each of said sleeves 13has in its conical zone a circular series of admission ports 14,registering with said ports 7 and opening inwardly from the admissionchamber 5, as shown in Figs. I and II. Said sleeves each have a circularseries of ports 15 opening inwardly from ill) till

said admission chamber 5 through the smaller cylindrical portions ofsaid sleeves, as shown in Figs. 1, 11 and 111. Each of said sleeves 13also has a circular series at ports 16 registering with the ports 11 andopening into said exhaust chamber 9, as shown in IV.

As shown in F .1 and 11; rotary tubular valves 17 are respectivelyfitted to turn within said stationary sleeves 13 and, as shown in Fig.111, said valve each have three circular series of ports 18, 19 and 21corresponding, in spacing, with said ports 14:, 15 and 16 and adapted tobe presented in or out of registry therewith, in accordance wth therotary position of said valves. Said ports '18 are in the conical zonesbetween the two cylindrical portions of each valve and said ports 19 and21 are in cylindrical. zones of the same, smaller, cylindrical portionof each valve. However, said ports 21 do not open directly into thespace within c id v". cause each of the cylinders of the engine iprovided with a stationary head 23, arranii to be-detachably bolted tosaid casing 1, and having a cylindrical portion 21: extending intotherespective valves 17 and having a circular series of portsregisterirg with said ports 16 in the sleeves 13, shown in 1V. As shownin Figs. ll, 11 and ill; I; find it convenient to form the outer ends ofsaid ports 25" in said heads 23 by sectoral bands 27 having thin edgesat the circumferential margins of said ports 25 and so shaped that theypress outwardly against the inner walls of said rotary valves 17 so asto tightly fit the latter, and prevent leakage to the exhaust chamber 9,from the piston chambers 28 in said valves which are closed by saidheads. I find it convenient to also provide each of said heads 23 withsealing rings 30 which are fitted in grooves there in and resilientlybear against the inner faces of said valves 17. it also lind itconvenient to form each of said heads 23 as a single hollow casting witha water chamber 31 herein, surrounding a central core 32 in which 1mount an ignition plug 1 plugs 34': are, or" course, suitably connectedin the ignition circuit of the engine and the water chambers 31 are alsoprovided with suitable piping connections, 111 COlnlillll'llC 2 tionwith the jacket recesses 12 and including means for circulating thewater therein.

The lower edge 01 said cylinder cas n 1 is rigidly connected with thecrank ho. 35-having threebearings 36 for the crank shaft 37, which hastwo cranks 38 extending radially oppositely from said shaft 37. As shownin Figs. 1 and 11; said cranks 38 are respectively connected with rods39 engaging the wrist pins 41 in the'respective pistons 42. Said pistonsd2 each have portions of two different diameters fitted to reciprocatein said valves 17 the outer smaller diameters thereof being providedwith resilient sealing rings a3, and the inner larger diameters there ofhaving similar sealing rings The construction and arrangement is suchthat said pistons 42 cooperate with said valves 17 to form between themcharging pump chainbers 16, as indicated in Fig. 1, to alternatelyintake fresh fluid from said adi'nission chant ber 5, and discharge thesame through the piston chambers 28, to drive out of the latter, throughsaid exhaust ports 25, 21, and 16, the products of combustion. That isto say, the peculiar construction and arrangement of valves and portsabove described automatically effects what is termed scavengingoperation, insuring the thorough elin'iination of all products oicombustion during each cycle of operation ot the engine.

The various ports above described are arranged to be automaticallyopened and closed at the proper times, by the continuous ro tation ofsaid valves 17. The means for effecting such rotation, as indicated inFig. I, include the miter gear i8, which is rigidly connected with said.crank shaft 37 and engaged with the miter gear 49 on the countershatt 50which is ournaled in the bearing 51 which is rigidly connected with saidcasing 1. Said countershaft 51 drives the pinion 52 which engages thegear 53 on the adjacent valve 17, which gear is in mesh with a similargear 53 on the other valve 17. I find it convenient to reduce thetricton of rotation of said valves by providing each of them with twoslip rings, 55 and 56, respectively upon axially opposite sides 0t theirgears 58. Said rings 55 bear against the inner ends of the sleeves 13,and said rings 56 bear against the outer. surtacesot the s toralabutment bearing blocks 57 which, as shown in Figs. 11 and V, aresupported by stepped flanges 58 in said cylinder casing 1. t

shown in Fig. V said bearing blocks 57 are respectively held by pairs ofcap screws 59 and are of such length that they may be inserted andremoved through the aps (5i and 62 at the opposite ends of said c 11 1;thus facilitating the assembling and dissembling oi said valves 17 withrespect to their seats in. the engine.

Each of the cylinders in said engine open ates alternately a powercylinder and as a charging cylinder. in the form above de scribed; aratio of tour to one has been chosen and each cylinder has four exhaustports 25, etc., reachingtij'om the outer ends 01" the combustionchambers 28 inward far enough to insure proper o 'iening area. The,width oi said ports 25 depends upon the relative opening and closingpoints of the ca;- haust ports 21 in said valves 17. The chargeadmission ports 15 are of double the numsuch admission ports isdetermined by the outer limits of the pistons 42. The width of saidadmission ports may be larger than that of the exhaust ports but islimited by the necessity for safe closing of the admission ports, by thevalves, before the pistons uncover them, as said admission ports areuncovered twice by the valves during one revolution of the engine, butonly once, at the proper time, by the pistons. The inlet ports are, ofcourse, opened when the pistons start inward but are closed when thepistons reach dead center inward, and the discharge ports are opened atthe beginning of the outward stroke of the pistons, as soon as thepressures in the charging chambers 46 and in the admission or receivingchamber 5 are equal, and said discharge ports close when the pistonsreach the dead center outward.

In Fig. VI; the steps in the operation as a power cylinder areindicated. The arrow in said figure indicates the direction of rotationof said crank shaft 37. In said figure, indicates the point where theexhaust opens, 66 indicates the point where the exhaust closes; and 67indicates the location of the piston for those two points. The chargeadmission ports 68 open at the point 68 and are closed, by the piston,at the point 69, immediately preceding said exhaust closing point 66.Although the charge admission ports begin to register with each other atthe point 7 O and are fully registered at the point 71 so that they arewide open, as far as the valves 17 are concerned, they do not then admitthe charge because they remaln covered by the pistons. The length of theports is determined with reference to the radial distance between thepoints 67 and 72 in Fig. VI.

In Fig. VII; the steps in the operation as a charging cylinder areindicated. The arrow in said figure indicates the direction of rotationof said crank shaft 37. The inlet ports start to open at the point 7 1and close at the point 75. The discharge ports open at the point 76 andclose at the point 78.

It mav be observed, with reference to Figs.

' I and II that when the cranks 38 are on opposite dead centers. thelarger portion of the piston 42 at the left of Fig. I, acting as acharging pumphas driven, from its charging chamber -16, a volume offluid, at least equal to the capacity of the power chamber 28, into thelatter, through the ports 15 and through said power chamber 28 to expelfrom the latter, through the ports 25, all of the products ofcombustion. At the same time, the piston 12 at the right of Fig. I hasdrawninto its charging chamber 46, a corresponding volume of fluid fromsaid admis sion chamber or fluid receiver 5; ready to charge the sameinto and through the power chamber 28 of the other cylinder, in duetime, in the cycle of operation.

The construction and arrangement above described has the followingadvantages:

First: A charge: of fresh combustible mixture, or air, is positivelydelivered to each power cylinder in the direction to produce the mostefficient scavenging effect therein, by elimination of products ofcombustion after each power stroke.

Second: The burnt gases are thus exhausted and the fresh charge ofcombustible mix ture admitted with the least possible chance of mixingwith each other.

Third: The pressure of the savenging charge is as low as possible; notbeing admitted until the exhaust pressure is practically equal to thatof the atmosphere.

Fourth: The exhaust valves are closed a trifle later than the beginningof the admis sion of the scavenging charge; thus insuring perfectfilling of the power chambers.

Fifth: The operation of the valves is positively eflected in propertime; thus avoiding the irregularity of operation, which is incident tothe operation of valves with springs.

Sixth: All passages are so short and direct as to reduce throttlingeffect to the minimum.

Seventh: The construction and arrangement is less complicated than priorengines.

Eighth: The means for holding the valves and their appurtenances inoperative posi tion renders them more easily accessible for primaryassembling and subsequent repairs than in such prior engines.

Ninth: The inside of each piston is entirely exposed to the coolingeffect of the air in the crank case.

Tenth: No stuffing box and extra cross head is required.

Eleventh: The parts of the valves at the hottest part of the engine, towit, the region adjoining the spark plugs, are cooled upon both outsideand inside.

Twelfth: The engine above described, with reference to Figs. I to VIIinclusive may be used as an oil engine, pumping air instead ot'combustible mixture; in which case the oil must be injected in vaporousform toward the end of each outer stroke of said pistons 42. However,such use does not involve any change in the construction and arrangementshown in said figures.

However, the advantages above enumerated are not restricted to thespecific design of my invention shown in Figs. I to VII inclusive. Forinstance, in Figs. VIII to XI inclusive I have shown a modified form ofmy invention including four cylinders, arranged in two pairs, so thatwhile two cylinders are operating with air, the other two are operatingwith combustible mixtures.

Referring to Figs. VIII to XI inclusive; the cylinder casing 81 issimilar to the easing 1 above described, in its general arrangement, inthat thecylinders, ofwhich there are four, are, lined with stationarysleeves 82 which are larger at their ;inner ends, than at their outerends, to; torm charging chambers 83 and.power;chambers 81 are thrustoutwardly, while the pistons in the inner adjoining cylinders in saidcasing 81 aredrawn inwardly, and vice vers Eaehot said stationarysleeves 82 has a rotary valve 01 tted to turn therein like the valves 17above described and similarly rotated by connection with said crankshaft 86.

As ing 81 has oppositely counterpart admission ports 92 and, 93 leadingto respective admission or receivingchambers 9a which have ports 95 inthe conical portions oi said sleeves 82,; opening inwardly and adaptedto register with ports 90 in'said sleeves 91, ieading intosaid chargingchambers 88. The chambers 97 extend oppositely to said chambers 9 1,beyond the transverse partitions08 upon respectivelyopposite des of thelongitudinal partitions 99insaid casing 81 ;Wl.'110l1 partitionsseparate said chambers from each other. Said chambers 97 are incommunication with ports 100 which, when registered with ports l0linisaid valves 01, lead into said power. or combustion chambers 84; sothat said cylinders and pistons are operative in pairs to alternatelypump air. and fuel.

The outer portion of said casing 81 .t'orms exhaust chambers 102 havingrespective outlets 103, and inclosing circular series of; ports 10%respectively encircling each of said sleeves 82 and in registry withports 106 in said sleeves. Said ports 104: and'lOtS registerwithcorresponding ports 107;in[the cylinder heads 108 which arerespectively rigidly-connected with said casing 81 and extend withinsaid valves 01; which latter have port-s 109 adapted to'register withsaid er-zhaust ,ports,-- in the manner ,above described i with referenceto the construction and arrangement showniin Figs. 1 to VII inclusive.Spark plugs are'indicated at 110.

' Fl XI shows the ste )S in the o aeration of the engine lastabovedescribed with the crank turning in the direction of the arrow insaid figure, 114 indlcating the point at which theexhaust opens, and 115the point stood that the left hand pair of cylinders may be used todeliver the; scavenging-air shown in IX and K, said cas-,

to all four cylinders, and that the right hand pairof cylinders maybeused-to deliver the combustible mixture. to all. four cylinders; the airand combustible mixture being. separately admitted to the casmgSlthrough. the-respective adn'nssion ports 92.

of cylindrical chambers therein, each having water jacket recesses inits inner wall, said recesses being; primarily open inwardly; saidcylinder casing havingsectoral stepped flanges in concentric relationwith the. respective axes of said cylindrical chambers therein; ofstationary cylindrical sleeves each forming theinnerwalls of said jacketrecesses, and two cylindrical chambers of diiierent dianiieters each ofsaid sleeves having respective circular series of ports in three zones;rotary tubular valves each having two portions of ditlerent diametersmounted to turn in. said sleeves, and having three circular, series 01ports arranged to vary the 'eil'ectivearea-of said ports i11.said

.shaft journaled in said shaft casing; the

larger diameters oi" said sleeves, and valves being nearer the crankshaft than the smaller diameters thereoit; pistons mounted toreciprocate in said sleeve valves, anduhaving orical portions of saidvalves; connecting rods respectively connecting said pistons with thecranks of said. shailt; each of said valves having, at the larger endthereof, an external series of gear teeth; the gear teeth of therespective valves 1beingintermeshed with each other; a gear pinionmeshed with the teeth of one of said valves; a countershaft. extendingtransversely to said shafts, and carrying said pinion; a bevel gearupon'the opposite end of said counter-shaft; a bevel gear upon saidcrank shaftin mesh with the bevel gear on said counter-shaft; and meansnormally maintaining said. valves in assembled position insaidcylindercasing, includsaid cylinder casing;

its inner wall, said recesses being primarily open inwardly; saidcylinder casing having sectoral flanges inconcentric relation with therespective axes of said cylindrical chambers therein; of stationarycylindrical sleeves each forn'iing the inner walls of said jacketrecesses, and two cylindrical chambers of different diameters; each ofsaid sleeves having respective circular series of ports in three zones;rotary tubular valves each having two portions of different diametersmounted to turn in said sleeves, and having three circular series ofports arranged to vary the effective area of said ports in said sleeves;a crank shaft casing, connected with a crank shaft journaled in saidshaft casing; the larger diameters of said sleeves and valves beingnearer the crank shaft than. the smaller diameters thereof; pistonsmounted to reciprocate in said valves, and having portions of twodiameters respectively fitted to slide in the two diameters of saidvalves; the larger diameters of said pistons cooperating with the largerdiameters of said valves to form pump chambers between them, arranged toalter nately intake and charge fluid into the combustion, power,chambers which are in the smaller diametrical portions of said valves;connecting rods respectively connecting said pistons with the cranks ofsaid shaft; each of said valves having, at the larger end there-of, anexternal series of gear teeth; the gear teeth of the respective valvesbeing intermeshed with each other; a gear pinion meshed with the teethof one of said valves; a countershaft, extending transversely to saidshafts, and carrying said pinion; a bevel gear upon the opposite end ofsaid countershaft; a bevel gear upon said crank shaft in mesh with thebevel gear on said countershaft; and means normally maintaining saidvalves in assembled position in said cylinder casing, including sectoralabutment bearing blocks seated upon said sectoral stepped flanges insaid cylinder casin 3. In an internal combustion engine; the combinationwith an outer cylinder casing, with a plurality of cylindrical chamberstherein, each having water jacket recesses in its inner wall, saidrecesses being primarily open inwardly; said cylinder casing havingsectoral flanges in concentric relation with the respective axes of saidcylindrical chambers therein; of stationary cylindrical sleeves eachforming the inner walls of said jacket recesses, and two cylindricalchambers of different diameters; each of said sleeves having respectivecircular series of ports; rotary tubular valves each having two portionsof different diameters mounted to turn in said sleeves, and havingcircular series of ports arranged to vary the effective area of saidports in said sleeves; a crank shaft casing; a crank shaft journaled insaid shaft casing; the larger diameters of said sleeves and valves beingnearer the crank shaft than the smaller diameters thereof; pistonsmounted to reciprocate in said valves, and having portions of twodiameters respectively fitted to slide in the two diameters of saidvalves; the larger diameters of said pistons cooperating with the largerdiameters of said valves to form pump chambers between them, arranged toalternately intake and charge fluid into the combustion, power, chamberswhich are in the smaller diametrical portions of said valves; connectingrods respectively connecting said pistons with the cranks of said shaft;each of said valves having, at the larger end thereof, an externalseries of gear teeth; the gear teeth of the respec tive valves beingintermeshed with each other; gear means operatively connecting saidvalve gears with said crank shaft; and means normally maintainingsaidvalves in assembled position in said cylinder casing, including sectoralabutment bearing blocks seated upon said sectoral flanges in saidcylinder casing.

4:. In an internal combustion engine; the combination with van outercylinder casing, with a plurality of cylindrical chambers therein; saidcylinder casing having sectoral flanges in concentric relation with therespective axes of said cylindrical chambers there in; of stationarycylindrical sleeves fitted in said casing chambers, and each forming twocylindrical chambers of different diameters; each of said sleeves havingrespective circular series of ports in three zones; one of said zonesbeing conical; rotary tubular valves each having two portions ofdifferent diameters mounted to turn in said sleeves, and having circularseries of ports arranged in three zones, fitted to said sleeve zones andarranged to vary the effective area of said sleeve ports; a crank shaftcasing, rigidly connected with said cylinder casing; a crank shaftjournaled in said shaft casing; the larger diameters of said sleeves andvalves being nearer the crank shaft than the smallor diameters thereof;pistons mounted to reciprocate in said valves, and having portions oftwo diameters respectively fitted to slide in the two diameters of saidvalves; the larger diameters of said pistons cooperating with the largerdiameters of said valves to form pump chambers bet-ween them, arrangedto alternately intake and charge fluid into the combustion, power,chambers which are in the smaller diametrical portions of said valves;means operatively connecting llO said pistons with the cranks of saidshaft; each ot-said valves having an external series of gear teeth; thegear teeth of the respective valves being llltiOlll'lQSlWtl with eachther; n'ieans opera Y connecting an id valve gears with sac ril shatt:and means nornially maintaining said valves in assembled position insaid cylinder casing, including sectoral abu ment bearing bloc-itsseated upon said sectoral stepped flanges in said cylinder casing.

5.111 an internal combustion engine; the combination with an outercylinder casing, with a plurality of cylindrical chambers therein; saidcylinder casing having sectoral flanges in concentric relation with therespective axes of said cylindrical chambers therein; of stationarycylindrical sleeves in said casing chambers forming two cylindricalchambers of different diameters; each of said sleeves having respectivecircular series of ports; rotary tubular-valves each having two portionsof diilerent diameters mounted to turn in said slcevesyand havingcircular series of ports arranged to vary the effective area of saidports in said sleeves; a crank shalt casing, connected with saidcylinder casing; a crank shait journaled in said shaft casing; pistonsmounted to reciprocate in said valves, and having portions of two diameters respectively fitted to slide in the two diameters of saidvalves; the larger diameters of said pistons cooperating with the largerdiameters of said valves to form pump chambers between them, arranged toalter nately intake and charge fluid into the combustion, power,chambers which are in the smaller diametrical portions of said valves;means opcratively connecting said pistons with said crankshaft; andJllLtllSllOlll'lUllY n'iaintaining said valves in assembled posh tioninsaid cylinder casing, including sec toral abutmentbearing blocks seatedupon said sectoral flanges in said cylinder casing.

6. In an=intcri al combustion engine; the combination with an outercylinder casing, with-a cylindrical chamber therein, having a waterjacketreccss inits inner wall, said recess being primarily openinwardly; said cylinder casinghaving sectoral flanges in concentricrelation with the axis of saidcylindrical chambcrtherein; of astationary cylindrical sleeve forming the inner walls of said jacketrecesses, and two cylindrical chambers of diherent diameters; saidsleeve having circular series ol ports in three zones; a rotary tubularvalve having two portions of different diametersmounted to turn: insai'dsleeve, andhaving three circular series ot ports arranged toregister with and vary the eltective area of said ports in saidsleeves;: a crank shattcasing, connected withi said fcyl'indercasing; acrank shattjournal'edw in 's id shaft casing; a piston mounted-toreciprocate in sa-id valve; and,

ol said valve to torm a pump chamber lie-1 tween them, arranged toalternately intake and charge fluid into the cornbiistimi, power;chamber which is in the smaller diamctrical portion of. said'valvc;means operatively connccti n g said piston with said crank shaft; andmeans normally maintaming said valve in assembled position in saidcylinder casing, including sectoral abutment bearing blocks seated uponsaid sectoral flanges in said cylinder casing.

'i". in an internal combustion engine; the

combination with an outer cylinder casing,

with a. cylindrical chamber therein; of a stationary cylindrical sleevefitted in said casing chamber and forming two cylindrical chambers oftwo diameters in coaxial rela ticn; a rotary cylindrical valve, fittedin said sleeve and ditl'crcnt diameters in co-anial relation; a pistonhaving two portions oil" ditlerent dian'ict-ers mounted to reciprocatein said valve, arranged to form a, combustion chamber between thesmaller diameter 01'. said piston, andthe smaller diameter of saidvalve, and to form a pump chamber between the larger diameter of saidpiston, and the larger diameter ot said valve; said sleeve and'valvehaving circular series of ports arranged to register with each other andto vary their el'l'ective area; and means arranged to continuouslyrotate said valve while: reciprocat g said piston; whereby said ports'insaid valve registerwith ports in said sleeve twice in each revolution,but only once while said ports arouncovcrcd by said piston; andauton'latically effect ascavenging? opera tion whereby the products ofcombustion in said combustion chambers aredischarged therefrom by fluidunder pressure from said pump chamber during the operation of saidstruct-in'e as a two cycle engine.

8. In an internal. combustion engine; the combination with an-outcrcylinder casing, with a cylindricalchamber therein, having a waterjacket recess in its inner wall, said recess beingxprimarily openinwardly; said cylinder casing having a sectoral flange in concentricrelation with the axis of said chamber; out a stationary cylindricalsleeve forming the inner wall said jacket recess and two cylindricalchambers of different diameters; and means normally maintain ingsaidsleeve in assembled position in said cylinder casing and preventingELI-YlE1l"111OY6- ment thereof, including a sect-oralabutment bearingblock seated upon said sectoral: flan sin said cylindercasingr 9. n1anwii'iteri ial combnstion'engine; tl1e-= combination with tourcylinders; of pistons respectively mounted toreciprocate in said lormingtwo piston chamberswof cylinders; a crank shaft having four cranks;means operatively connecting said cranks with said pistons; and valvemeans in 00- axial relation with said pistons and operatively connectedwith said crank shaft, constructed and arranged to effect a two cycleoperation of the engine; means arranged to prevent axial movement ofsaid valve means;

said cylinders and pistons being arranged in pairs operative to pump airand fuel alternately; one pair pumping air While the other pair ispumping gas.

In testimony whereof, I have hereunto signed my name at Philadelphia,Pennsylvania, this 22nd day of September, 1924.

' MARTIN PLASS.

